The present invention relates to a self-propelled crushing machine for crushing thrown rocks, concrete, woods and the like and discharging to an outer portion.
There exist various kinds of self-propelled crushing machines for crushing rocks, for crushing concrete, for crushing woods and the like. For example, the self-propelled crushing machine for crushing woods has, as shown in FIGS. 1 and 2, a rotary crusher 1 and a rotary tub 3 which introduces a wood 2 thrown from an outer portion to the rotary crusher 1 due to a rotation on a self-propelled truck 4, crushes the wood 2 introduced from a rotary tub 3 to the rotary crusher 1 and discharges to the outer portion. The details are as follows.
The rotary crusher 1 is a so-called hammer mill. This has a plurality of cutters 1b on an outer periphery of a shaft 1a which is structured to be made rotatable by crusher drive means, and crushes the wood 2 by the cutters 1b. The crusher drive means is driven by an oil hydraulic pressure, directly driven or the like.
The rotary tub 3 has a funnel 3b which is made rotatable by the tub drive means on a fixed bottom plate 3a. A part of the fixed bottom plate 3a is open, and the cutters 1b of the rotary crusher 1 can be overviewed from the opening. The tub drive means is also of an oil hydraulic driven type, a direct driven type or the like.
When throwing the wood 2 having a long size into the rotary tub 3, a lower end of the wood 2 is brought into contact with the upper portion of the fixed bottom plate 3a and the cutters 1b within the opening. On the contrary, the wood 2 falls down and an upper side surface thereof is brought into contact with an inner wall of the funnel 3b. A plurality of convex portions are provided on the inner wall of the funnel 3b in a vertical direction, and the convex portion presses the wood 2 due to a rotation of the funnel 3b. As a result, the lower end of the wood 2 reciprocates between the upper portion of the fixed bottom plate 3a and the cutter 1b while the wood 2 changes an attitude thereof, so that even the long wood 2 can be crushed by the cutters 1b. The crushed wood 2 is used for a pulp raw material, a manure, a fuel and the like.
In this case, the self-propelled crushing machine is structured such that when the raw materials are large or hard, or when they are mixed with the small raw materials or the soft raw materials, a load of the crusher is increased, a rotational speed is reduced, and a crushing efficiency is lowered. The reduction of the rotational speed causes a breakage of the crusher. Then, there is a structure made such as to automatically stop a raw material supply apparatus (the rotary tub 3 in the case of being used for crushing the wood) when the rotational speed of the crusher is lowered to a predetermined value Nb, and to automatically start the raw material supply apparatus when the rotational speed of the crusher is inversely increased to a predetermined value Na. In this case, in order to prevent the automatic stop and the automatic start from generating a hunting, a relation between the predetermined values Na and Nb is set to, for example, a relation Na greater than Nb+50 rpm.
However, the prior art mentioned above has the following problems.
(1) Since the raw material supply apparatus is automatically started or automatically stopped in accordance with a rotational change of the crusher, there is no function for automatically returning the crusher to a normal rotation although the reason of breaking the crusher is solved. Accordingly, a reduction of a crushing efficiency is unavoidable.
(2) A crushed grain size (a piece size in the case of the crusher for crushing the wood) becomes finer as the rotational speed of the crusher becomes higher. If the normal rotational speed of the crusher is set to Ns, a relation Ns greater than Na and Ns greater than Nb is established. In this case, since the relation Na greater than Nb is established as mentioned above, the changing range of the rotational speed of the crusher becomes wide to Ns to Nb. Accordingly, it is hard to obtain the crushed material having a fixed grain size.
(3) In particular, the self-propelled crushing machine for crushing the wood has the rotary tub, however, there has not been suggested a technique structured such as to preferably control the rotational speed and perform a crushing having a higher efficiency.
(4) The start and stop of the rotary tub depend only upon the rotational change of the crusher, and the rotary tub itself does not have an automatic control function. Further, the breakage of the crusher is indirectly prevented by the automatic start and the automatic stop of the rotary tub, and the crusher itself does not have an automatic control function.
(5) For example, when a long member made of a wood 2 and the like is held-between the convex portion of the rotary tub 3 and the cutters 1b, a rotational force of the rotary tub 3 pushes the cutter via the wood 2. Accordingly, an excess load is generated in the rotary crusher 1, and the rotational speed is suddenly reduced. However, in the self-propelled crushing machine for crushing the wood 2, there is an operational effect that the rotary tub 3 is further rotated, so that the nipped wood 2 is taken out and the crushing is again started. In the case that the predetermined value Na is set so as to automatically stop the rotary tub 3, as in the prior art, this operational effect can not expected. On the contrary, when the thick and hard wood 2 is completely meshed with the cutters 1b, it is impossible to discharge the meshed wood 2 only by the automatic stop of the rotary tub 3 as in the prior art and it is necessary to discharge the wood 2 by human hands, so that the crushing efficiency is bad.
The present invention is made by taking the conventional problems mentioned above into consideration, and an object of the present invention is to provide a self-propelled crushing machine in which a crushed material having a widely desired grain size can be obtained, a degree of freedom for automatically controlling a rotary tub and a crusher can be preferably improved, and a crushing having a high efficiency can be performed.
In accordance with a first aspect of the present invention, there is provided a self-propelled crushing machine in which a rotary crusher and a rotary tub for introducing a material to be crushed thrown from an outer portion to the rotary crusher are provided on a self-propelled truck, and the material to be crushed which is introduced from the rotary tub is crushed by the rotary crusher and freely discharged to the outer portion, comprising target crushing rotational speed setting means for setting a target crushing rotational speed Nhm of the rotary crusher, actual crushing rotational speed detecting means for detecting an actual crushing rotational speed Nh of the rotary crusher, crusher drive means for setting the rotary crusher to be freely rotated, and control means for inputting a target crushing rotational speed Nhm from the target crushing rotational speed setting means, inputting the actual crushing rotational speed Nh from the actual crushing rotational speed detecting means and outputting a crushing rotation control signal Nhn for maintaining a relation Nhxe2x88x92Nhm=0 to the crusher drive means by comparing them.
In accordance with the first aspect, since the control means maintains the relation Nhxe2x88x92Nhm=0, it is possible to obtain a crushed material having a fixed grain size. Further, it is possible to freely set the target crushing rotational speed Nhm by the target crushing rotational speed setting means. Accordingly, it is possible to set an optimum target crushing rotational speed Nhm with respect to the materials to be crushed which are different in a hardness, a shape, a size and a batch, whereby the crushed material having a fixed grain size can be obtained. Further, it is possible to widely obtain the crushed material having a different grain size by variously changing the target crushing rotational speed Nhm with respect to the same material to be crushed.
In accordance with a second aspect, there is provided a self-propelled crushing machine as cited in the first aspect, further comprising tub drive means for making the rotary tub rotatable, and control means for inputting a target crushing rotational speed Nhm from the target crushing rotational speed setting means, inputting the actual crushing rotational speed Nh from the actual crushing rotational speed detecting means, outputting a crushing rotation control signal Nhn for maintaining a relation Nhxe2x88x92Nhm=0 to the crusher drive means by comparing them, and outputting a tub rotation control signal Ntn to the tub drive means.
In accordance with the second aspect, the tub drive means for setting the rotary tub rotatable is provided and the control means outputs the tub rotation control signal Ntn to the tub drive means. As mentioned above, since the control means can freely control the rotational speed of the rotary tub corresponding to a second reason for further efficiently performing a crushing operation, a crushing operation having a high efficiency can be performed.
In accordance with a third aspect, there is provided a self-propelled crushing machine as cited in the second aspect, further comprising control means for freely setting a rotational speed Nh0 having a relation Nh0 less than Nhm which is smaller than the target crushing rotational speed Nhm, and respectively outputting a tub rotation control signal Nt1 for normally rotating the rotary tub, a tub rotation control signal Nt2 for gradually reducing a positive rotational speed Nt in accordance with a reduction of the actual crushing rotational speed Nh, and a tub rotation control signal Nt3 for inversely rotating the rotary tub or stopping the rotary tub to the tub drive means when the actual crushing rotational speed Nh satisfies a relation Nhxe2x89xa7Nhm, a relation Nhm greater than Nh greater than Nh0, and a relation Nhxe2x89xa6Nh0.
In accordance with the third aspect, the following operational effects can be obtained.
The relation Nhxe2x89xa7Nhm corresponds to a state in which the actual crushing rotational speed Nh of the rotary crusher has a normal positive rotational speed. At this time, it is necessary that the rotary tub has a normal positive rotational speed, and this is compensated by the tub rotation control signal Nt1.
Further, the crushing rotational speed Nh0 of the rotary crusher has a relation Nh0 less than Nhm with respect to the target crushing rotational speed Nhm and can be freely set.
In this case, the relation Nhm greater than Nh greater than Nh0 corresponds to a state in which the actual crushing rotational speed Nh is lowered to a value immediately before the crushing rotational speed Nh0 expected to be a standard due to an increase of a load of the rotational crusher, so that it is desired to be quickly returned to the target crushing rotational speed Nhm. At this time, if the rotational speed of the rotary tub is a fixed rotation as in the prior art, the returning is delayed or the cutter is broken. However, in accordance with the third aspect, the control means 16 outputs the tub rotation control signal Nt2 for gradually reducing the positive rotational speed Nt of the rotary tub in correspondence to the actual crushing rotational speed Nh. Accordingly, the load of the rotation of the rotary crusher is reduced and it is easy to return to the target crushing rotational speed Nhm. That is, it is possible to widely obtain the crushed material having a desired grain size, and it is possible to increase a crushing efficiency.
The relation Nhxe2x89xa6Nh0 corresponds to a state in which the actual crushing rotational speed Nh becomes the rotational speed Nh0 expected to be a standard or equal to or less than the value. At this time, the control means 16 outputs the tub rotation control signal Nt3 for inversely rotating the rotary tub 3 or stopping the rotary tub 3. Accordingly, there is generated a chance that the meshing of the material to be crushed with the cutter 1b corresponding to a reason of reducing the actual crushing rotational speed Nh is automatically excluded. In this case, since the generation of the meshing (an increase of the load) mentioned above itself becomes rare due to the operational effect of the relation Nhm greater than Nh greater than Nh0, it is possible to further increase the crushing efficiency due to the operational effect of the relation Nhxe2x89xa6Nh0.
In accordance with a fourth aspect, there is provided a self-propelled crushing machine as cited in the third aspect, further comprising gradual reduction degree setting means for previously setting a degree f(L) of a gradual reduction of the rotational speed of the rotary tub.
In accordance with the fourth aspect, a further higher crushing efficiency can be achieved by setting the degree f(L) of the gradual reduction in correspondence to the state of the material to be crushed when gradually reducing the positive rotational speed Nt of the rotary tub. That is, the rotational speed of the rotary tub as well as the rotary crusher can be easily converged to the normal rotational speed by previously setting the degree f(L) of the gradual reduction at each of the hardness, the shape, the size, the amount and the like of the material to be crushed. The degree f(L) of the gradual reduction is given by, for example, tub gradual reduction functions f(La) to f(Lc) shown in FIGS. 5A to 5C.
In accordance with a fifth aspect, there is provided a self-propelled crushing machine comprising crusher load detecting means for detecting an actual rotational speed Nh of a rotary crusher for crushing a material to be crushed as a load, crusher overload judging means for inputting the actual rotational speed from the crusher load detecting means, comparing with a predetermined lower limit speed No and judging an overload of the rotary crusher, and positive and inverse rotating and stopping means for inputting an overload information from the crusher overload judging means and inversely rotating the rotary crusher.
In accordance with the fifth aspect, the crusher overload judging means inputs the actual rotational speed Nh from the crusher load detecting means so as to compare with the predetermined lower limit speed No, judges the overload of the rotary crusher, and outputs the overload information to the crusher inversely rotating means so as to inversely rotate the rotary crusher. The state that the load of the rotary crusher becomes excessive corresponds to the state that the material to be crushed are meshed therewith. However, since the rotary crusher is automatically rotated in an inverse direction due to the overload, the meshing of the material to be crushed can be automatically cancelled or the meshing can be easily removed by human hands. Accordingly, a crushing efficiency is increased. Further, since the rotary crusher itself controls its own state in accordance with the overload information, the degree of freedom for the control can be increased at that degree.
In accordance with a sixth aspect, there is provided a self-propelled crushing machine as cited in the fifth aspect, further comprising crusher overload judging means for judging an overload of the rotary crusher and judging that a number n2 of generating the overload becomes a predetermined number n20 within a predetermined time t20, and positive and inverse rotating and stopping means for stopping the rotary crusher when the overload generation number n2 from the crusher overload judging means becomes the predetermined number n20 within the predetermined time t20.
The crusher overload judging means in accordance with the sixth aspect is structured such as to further judge a time when the overload generation number n2 becomes the predetermined number n20 within the predetermined time t20 and stop the rotary crusher by the positive and inverse rotating and stopping means at that time. Accordingly, the rotary crusher automatically stops when an abnormal matter is generated. Accordingly, the rotary crusher is not broken and the crushing efficiency is further improved.
In accordance with a seventh aspect, there is provided a self-propelled crushing machine comprising tub load detecting means for detecting a load of a rotary tub for introducing a material to be crushed, tub overload judging means and positive and inverse rotating and stopping means for inversely rotating the rotary tub.
In accordance with the seventh aspect, the tub overload judging means can judge an overload of the tub on the basis of the information from the tub load detecting means, and can instruct an inverse rotation of the tub to the tub inverse rotating means. The overload of the rotary tub is caused by the case that the material to be crushed are meshed with the rotary crusher and the overload is indirectly involved in addition to the case that the rotary tub itself is under an overload. However, since the inverse rotation of the tub is automatically performed due to the overload, the meshing of the material to be crushed with the rotary crusher can be automatically cancelled, and the overload of the rotary tub itself can be cancelled. Accordingly, it is possible to stably rotate the rotary tub and the rotary crusher for a long time, and a crushing efficiency is significantly high. Further, since the rotary tub itself is controlled by the overload information of the rotary tub itself, the degree of freedom for the control is increased at that degree.
In accordance with an eighth aspect, there is provided a self-propelled crushing machine as cited in the seventh aspect, further comprising tub overload judging means for judging that an inverse rotation number n1 of the rotary tub by the positive and inverse rotating and stopping means becomes a predetermined inverse rotation number n10 within a predetermined time t10, and positive and inverse rotating and stopping means for inputting the overload information from the tub overload judging means and stopping the rotary tub.
The tub overload judging means in accordance with the eighth aspect is structured such as to further judge a time when the inverse rotation number n1 of the rotary tub by the tub inverse rotating means becomes the predetermined inverse rotation number n10 within the predetermined time t10, and output the overload information to the tub stopping means so as to stop the rotary tub. Accordingly, the rotary tub automatically stops when an abnormal matter is generated, so that the rotary tub and the rotary crusher is prevented from breaking, and a crushing efficiency is further increased.
In accordance with a ninth aspect, there is provided a self-propelled crushing machine comprising crusher load detecting means for detecting a load of a rotary crusher for crushing a material to be crushed, crusher overload judging means, tub load detecting means for detecting a load of a rotary tub for introducing the material to be crushed, tub overload judging means, and positive and inverse rotating and stopping means for positively and inversely rotating and stopping the rotary crusher and the rotary tub.
The ninth aspect is structured such as to substantially combine the fifth aspect and the seventh aspect. The ninth aspect is different from the fifth and seventh aspects in a point that the overload is obtained on the basis of the rotational speed Nh in the fifth and seventh aspects, however, the ninth aspect does not limit to the rotational speed Nh but a torque, an oil hydraulic pressure and the like can be replaced thereto. Therefore, in accordance with the ninth aspect, as well as the operational effects of the fifth and seventh aspects can be obtained, an applicable range thereof can be further expanded.
In accordance with a tenth aspect, there is provided a self-propelled crushing machine comprising crusher load detecting means for detecting an actual rotational speed Nh of a rotary crusher for crushing a material to be crushed as a load, crusher overload judging means for inputting the actual rotational speed Nh from the crusher load detecting means so as to compare with a predetermined lower limit speed No and judging an overload of the rotary crusher, tub load detecting means for detecting a load of a rotary tub for introducing the material to be crushed, tub overload detecting means for detecting an overload of the rotary tub, tub overload judging means for inputting a tub overload signal P1 from the tub overload detecting means so as to judge an overload of the rotary tub, and positive and inverse rotating and stopping means for inversely rotating the rotary tub when at least one of the crusher overload judging means and the tub overload judging means judges the overload.
In accordance with an eleventh aspect, there is provided a self-propelled crushing machine as cited in the tenth aspect, wherein the crusher overload judging means and the tub overload judging means add an inverse rotation number n1 obtained by inversely rotating the rotary tub, and stop the rotary tub by the positive and inverse rotating and stopping means when the number n1 reaches a predetermined inverse rotation number n10.
Since these tenth and eleventh aspects correspond to a combination of the structures of the fifth to ninth aspects mentioned above, the operational effects of the fifth to ninth aspects can be obtained in an overlapping manner, and since the structure is made such as to judge the overload of the rotary tub by inputting the tub overload signal also from the tub overload detecting means, it is possible to further select an accuracy of a control and a degree of freedom in correspondence to an object of crushing